Photochemical smog, history

Fig. VI-9. Concentration-lime history or reactants and some products in the photooxidation of C3H. Mixtures of C,H4 + NO + NOj in air were irradiated by simulated sunlight in smog chamber. Reprinted with permission from H. Niki, C. E. Daby, and B. Weinstock, in Photochemical Smog and Ozone Reactions, R. F. Gould, Ed., American Chemical Society, Washington, D. C. Copyright by the American Chemical Society, 1972. 

Coincidentally, the place Plutarch suggested as best for writing a history, a city, or urban area, is where photochemical smog and associated air pollutants were first observed and peroxyacetyl nitrate (PAN) was first identified as a potentially important air pollutant. The discovery of PAN has an interesting history. It is a story based on collaboration and discussion between biologists and chemists, leading to identification of a unique family of molecules, the peroxyacyl nitrates (PANs), which are now just beginning to be appreciated as important compounds for measurement in the free troposphere, as well as in urban air. 

History /application note Important prodact of internal combustion engine leading to photochemical smog neurotransmitter. blood pressure regulator... 

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